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151.
CeO_2/Al_(0.2)Ti_(0.6)Zr_(0.2)O_(1.9)/ATS复合脱硝催化剂的制备及其抗硫抗水性能研究 总被引:1,自引:1,他引:0
将预先经酸处理的铝钛硅(ATS)多相陶瓷片先后负载Al0.2Ti0.6Zr0.2O1.9复合氧化物与CeO2活性组分,制得新型CeO2/Al0.2Ti0.6Zr0.2O1.9/ATS复合脱硝催化剂。运用X射线衍射(XRD)、扫描电镜(SEM)手段对该催化剂进行表征,研究催化剂的晶相、微观形貌。评价了催化剂的脱硝活性,研究了H2O和SO2对其脱硝活性的影响。实验结果表明,CeO2/Al0.2Ti0.6Zr0.2O1.9/ATS具有良好的脱硝活性,高活性温度窗口在100~350℃,当反应温度为250℃时,NO的转化率达98.49%。SO2和H2O在一定程度抑制该催化剂的低温脱硝活性,但随着温度的升高,其脱硝活性逐渐恢复。催化剂中活性组分CeO2具有储硫作用,当有SO2存在时,活性温度窗口向高温区偏移了100℃,在250~400℃时,H2O的存在反而提高了催化剂的脱硝活性。 相似文献
152.
介绍了中小型工业窑炉生产过程中排放NOx的现状,并针对NOx的治理问题,从工程应用角度,简述了湿法和干法净化NOx的原理和化学反应过程。讨论了NOx排放特性和NOx废气中NO2/NOx比例的问题。提出了影响NOx治理的主要因素,包括吸收剂、吸附剂、催化剂和设备的部分应用参数,并结合工程实例指出工程需要注意的问题。介绍了多项采用湿法和干法净化NOx的工程应用项目,丰富了中小工业窑炉NOx废气的治理的实践经验,为中小工业窑炉排放NOx治理奠定了基础。 相似文献
153.
X.X. Zhang P.J. Shi L.Y. Liu Y. Tang H.W. Cao X.N. Zhang X. Hu L.L. Guo Y.L. Lue Z.Q. Qu Z.J. Jia Y.Y. Yang 《Atmospheric environment (Oxford, England : 1994)》2010,44(13):1641-1648
Based on environmental monitoring data in 93 major cities and meteorological records at 398 weather stations in China from 1981 to 2007, total suspended particle (TSP) concentration, the intensity of dustfall, and sand and dust storm frequency (Fd) were analysed. During the past 27 years, the annual average TSP concentration (CTSP) in 93 cities was 402 μg m?3. Annual average CTSP decreased from the north to the south and from inland to the coast areas with a peak value of 628.8 μg m?3 in Lanzhou. In the 1980s, 1990s and 2000s, annual average CTSP was 628.7, 319.2, and 250.1 μg m?3, respectively. Annual average intensity of dustfall (Id) was 240.5 t km?2 a?1, decreased from northern to southern China and from inland to the coast areas with the maximum value of 717.2 t km?2 a?1 in Baotou. In the 1980s, 1990s and 2000s, annual average Id was 334.8, 220.9, 146 t km?2 a?1 respectively. Annual average Id in the Loess Plateau region was commonly higher than 200 t km?2 a?1. The annual average Fd decreased from arid regions in northwestern China to humid areas in southeastern China with two sand and sand storm centers existing in Xinjiang Taklamakan Desert and western Inner Mongolia. The annual average Fd in the 1980s, 1990s, 2000s was 16, 8, 6 days respectively, decreased steadily from 18 days in 1981–5 days in 2007. Annual average Id had a positive linear relation to annual average CTSP (R2 = 0.96). Annual average Fd had a positive relation with annual average CTSP (R2 = 0.97) as well as annual average Id (R2 = 0.94). TSP was the chief pollutant influencing Air Pollution Index (API) in northern China in spring and winter seasons. Sand and dust storm might be a major factor affecting the temporal variability and spatial distribution of TSP and dustfall in China. 相似文献
154.
Guofeng Shen Wei Wang Yifeng Yang Chen Zhu Yujia Min Miao Xue Junnan Ding Wei Li Bin Wang Huizhong Shen Rong Wang Xilong Wang Shu Tao 《Atmospheric environment (Oxford, England : 1994)》2010,44(39):5237-5243
Coal consumption is one important contributor to energy production, and is regarded as one of the most important sources of air pollutants that have considerable impacts on human health and climate change. Emissions of polycyclic aromatic hydrocarbons (PAHs) from coal combustion were studied in a typical stove. Emission factors (EFs) of 16 EPA priority PAHs from tested coals ranged from 6.25 ± 1.16 mg kg?1 (anthracite) to 253 ± 170 mg kg?1 (bituminous), with NAP and PHE dominated in gaseous and particulate phases, respectively. Size distributions of particulate phase PAHs from tested coals showed that they were mostly associated with particulate matter (PM) with size either between 0.7 and 2.1 μm or less than 0.4 μm (PM0.4). In the latter category, not only were more PAHs present in PM0.4, but also contained higher fractions of high molecular weight PAHs. Generally, there were more than 89% of total particulate phase PAHs associated with PM2.5. Gas-particle partitioning of freshly emitted PAHs from residential coal combustions were thought to be mainly controlled by absorption rather than adsorption, which is similar to those from other sources. Besides, the influence of fuel properties and combustion conditions was further investigated by using stepwise regression analysis, which indicated that almost 57 ± 10% of total variations in PAH EFs can be accounted for by moisture and volatile matter content of coal in residential combustion. 相似文献
155.
3种浮床植物系统对富营养化水体净化效果研究 总被引:10,自引:3,他引:7
研究了风车草(Cyperus alternifolius)、菖蒲(Acorus calamus)和富贵竹(Dracaena sanderiana)3种浮床植物系统对富营养化水体净化效果,试验共持续35 d。结果表明,在水温24~30℃条件下,风车草和菖蒲生长良好,生物量大,而富贵竹生长较差,生物量增加少;3种植物对NH_4~+-N的去除率分别为76.8%、85.5%和53.6%,对TN的去除率分别为69.1%、66.2%和54.4%,对TP的去除率分别为76.9%、84.6%和61.5%,对PO_4~(3-)-的去除率分别为91.7%、91.7%和75%,对真实色度有明显的去除效果;3种植物对氮磷和真实色度去除效果与对照之间均达到显著差异(P0.05),自然沉淀是浊度去除的主要原因,植物吸收同化作用是NH_4~+-N去除的主要途径,植物吸收是溶解性磷去除的主要途径。试验表明,风车草和菖蒲对富营养化水体中氮磷和真实色度有较好的去除效果,可作为富营养化水体治理的优良物种而推广使用。 相似文献
156.
157.
L.Q. Xu L.G. Sun H. Yan Y.H. Luo Y.H. Wang 《Journal of environmental radioactivity》2010,101(5):362-368
Several natural and anthropogenic radionuclides (210Pb, 226Ra and 137Cs) in guano-phosphatic coral sediments and pure guano particles collected from Ganquan, Guangjin, Jinqing and Jinyin Islands of the Xisha archipelago, South China Sea, were analyzed. The Constant Initial Concentration (CIC) model and the Constant Rate of Supply (CRS) model were applied for age calculation. The average supply rate of 210Pb was 126 Bq m−2 a−1, very close to the flux of northern hemisphere average (125 Bq m−2 a−1). The activities of anthropogenic radionuclides in the sediments were very low, indicating that human nuclear tests did not notably impact this region. The main source of radionuclides in the sediments was from atmospheric precipitation, and the organic matter derived from plant and produced by nutrient-rich guano could further enhance them. 相似文献
158.
Po-Min Kao Min-Che Tung Bing-Mu Hsu Yi-Chou Chiu Cheng-Yu She Shu-Min Shen Yu-Li Huang Wen-Chien Huang 《Environmental science and pollution research international》2013,20(9):6128-6137
In this study, a SYBR green quantitative real-time PCR was developed to quantify and detect the Legionella spp. in various environmental water samples. The water samples were taken from watershed, water treatment plant, and thermal spring area in Taiwan. Legionella was detected in 13.6 % (24/176), and the detection rate for river water, raw drinking water, and thermal spring water was 10, 21.4, and 16.6 %, respectively. Using real-time PCR, concentration of Legionella spp. in detected samples ranged between 9.75?×?104 and 3.47?×?105?cells/L in river water, 6.92?×?104 and 4.29?×?105?cells/L in raw drinking water, and 5.71?×?104 and 2.12?×?106?cells/L for thermal spring water samples. The identified species included Legionella pneumophila (20.8 %), Legionella jordanis (4.2 %), Legionella nautarum (4.2 %), Legionella sp. (4.2 %), and uncultured Legionella sp. (66.6 %). The presence of L. pneumophila in aquatic environments suggested a potential public health threat that must be further examined. 相似文献
159.
X. Q. Liang Z. Y. Nie M. M. He R. Guo C. Y. Zhu Y. X. Chen Küppers Stephan 《Environmental science and pollution research international》2013,20(10):6972-6979
One strategy to combat nitrate (NO3-N) contamination in rivers is to understand its sources. NO3-N sources in the East Tiaoxi River of the Yangtze Delta Region were investigated by applying a 15N–18O dual isotope approach. Water samples were collected from the main channel and from the tributaries. Results show that high total N and NO3-N are present in both the main channel and the major tributaries, and NO3-N was one of the most important N forms in water. Analysis of isotopic compositions (δ 18O, δD) of water suggests that the river water mainly originated from three tributaries during the sampling period. There was a wide range of δ 15N-NO3 (?1.4 to 12.4 ‰) and a narrow range of δ 18O-NO3 (3.7 to 9.0 ‰) in the main channel waters. The δ 15N and δ 18O-NO3 values in the upper, middle, and lower channels along the river were shifted as 8.2, 3.5, and 9.5 ‰, and 9.0, 4.2, and 6.0 ‰, respectively. In the tributary South Tiao, the δ 15N and δ 18O-NO3 values were as high as 9.5 and 7.0 ‰, while in the tributaries Mid Tiao and North Tiao, NO3-N in most of the samples had relatively low δ 15N and δ 18O-NO3 values from 2.3 to 7.5 ‰ and 4.7 to 7.0 ‰, separately. Our results also suggest that the dual isotope approach can help us develop the best management practice for relieving NO3-N pollution in the rivers at the tributary scale. 相似文献
160.
Enfeng Liu Enlou Zhang Kai Li Bibhash Nath Yanling Li Ji Shen 《Environmental science and pollution research international》2013,20(12):8739-8750
Atmospheric lead (Pb) pollution during the last century in central Yunnan province, one of the largest non-ferrous metal production centers in China, was reconstructed using sediment cores collected from Fuxian and Qingshui Lakes. Lead concentrations and isotopic ratios (207Pb/206Pb and 208Pb/206Pb) were measured in sediment cores from both lakes. The operationally defined chemical fractions of Pb in sediment core from Fuxian Lake were determined by the optimized BCR procedure. The chronology of the cores was reconstructed using 210Pb and 137Cs dating methods. Similar three-phase variations in isotopic ratios and enrichment factors of Pb were observed in the sediment cores from both lakes. Before the 1950s, the sediment data showed low 207Pb/206Pb and 208Pb/206Pb ratios and enrichment factors (EFs?=?~1), indicating that the sedimentary Pb was predominantly of lithogenic origin. However, these indices were increased gradually between the 1950s and the mid-1980s, implying an atmospheric Pb deposition. The EFs and isotopic ratios of Pb reached their peak during recent years, indicating aggravating atmospheric Pb pollution. The average anthropogenic Pb fluxes since the mid-1980s were estimated to be 0.032 and 0.053 g m?2 year?1 recorded in Fuxian and Qingshui cores, respectively. The anthropogenic Pb was primarily concentrated in the reducible fraction. Combining the results of Pb isotopic compositions and chemical speciations in the sediment cores and in potential sources, we deduced that recent aggravating atmospheric Pb pollution in central Yunnan province should primarily be attributed to regional emissions from non-ferrous metal production industries. 相似文献